(a) Field of the Invention
The present invention is related to a vibration sensor, and more particularly, to one that can be built in an object (e.g., apparels, clothes, hats, shoes) for selectively turning on or off a power source and an electronic device connected to the vibration sensor and producing intermittent conduction.
(b) Description of the Prior Art
As illustrated in FIGS. 1 and 2 of the accompanying drawings, a roller vibration switch 1 of the prior art includes a free rolling ball 12 contained in a tube 11 with one end closed; and upper ends of two conductive pins 13, 14 disposed at the open end of the tube 11 enter into the tube 11 for the ball 12 to maintain conducted status while contacting both conductive pins 13, 14. When external vibration is introduced for the ball 12 to jolt, both conductive pins 13, 14 will indicate On or Off status thus to produce control signals to an electronic device to execute necessary control.
However, the construction of the prior art is found with the following limitations and defectives in practical operation:
1. As the ball 12 is contained in a cylindrical tube 11 and only two contacts are provided at its lower end, the tube 11 must be erected in standing status and any excessive tilt of the tube 11 will prevent the ball 12 from contacting both conductive pins 13, 14, thus to lose the results of sensing by vibration.
2. Even the vibration sense can be achieved with the erection of the tube allowed within a certain range of inclination, the central gravity of the ball 12 contained in the tube 11 would have to lean to one side to significantly reduce the sensitivity of the vibration induced, or malfunction in serious case. Therefore, to protect the vibration sensitivity from being significantly affected and to prevent the chance of malfunction, the range of the tilt angle allowed has to be very narrow, and further to put the erection angle and position of the tube 11 under extremely restriction.
3. When the ball 12 contacts only two conductive pins 13, 14, the vibration detection accuracy will not be consistent with regard to all vibration from all directions.
4. If the electronic device is not turned off, the ball 12 can be easily contacted in the course of transportation or display of the product to, thereby, consume all of the power supplied by the cell.